Fuel tank safety valve

ABSTRACT

A valve assembly for a fuel tank system including a fuel tank having a fuel tank outlet and a purge canister includes a main valve and a safety check valve. The main valve can be configured to move from a closed position to an open position. The main valve can have a main valve first port fluidly coupled to the outlet of the fuel tank and a main valve second port fluidly connected to the purge canister. The safety check valve can be configured to move from an open position to a closed position upon a pressure drop at the fuel tank outlet exceeding a predetermined threshold. The safety check valve can have a safety check valve first port fluidly coupled to the outlet of the fuel tank and a safety check valve second port fluidly coupled to the purge canister.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation U.S. patent application Ser. No.15/846,412 filed Dec. 19, 2017, which is a continuation of InternationalApplication No. PCT/US2016/038361 filed Jun. 20, 2016, which claims thebenefit of U.S. Patent Application No. 62/182,164 filed on Jun. 19, 2015and U.S. Patent Application No. 62/191,303 filed on Jul. 10, 2015. Thedisclosures of the above applications are incorporated herein byreference.

FIELD

The present disclosure relates generally to fuel tanks on passengervehicles and more particularly to a fuel tank valve configuration havinga main valve and a safety valve.

BACKGROUND

Fuel vapor emission control systems are becoming increasingly morecomplex, in large part in order to comply with environmental and safetyregulations imposed on manufacturers of gasoline powered vehicles. Alongwith the ensuing overall system complexity, complexity of individualcomponents within the system has also increased. Certain regulationsaffecting the gasoline-powered vehicle industry require that fuel vaporemission from a fuel tank's ventilation system be stored during periodsof an engine's operation. In order for the overall vapor emissioncontrol system to continue to function for its intended purpose,periodic purging of stored hydrocarbon vapors is necessary duringoperation of the vehicle.

The background description provided herein is for the purpose ofgenerally presenting the context of the disclosure. Work of thepresently named inventors, to the extent it is described in thisbackground section, as well as aspects of the description that may nototherwise qualify as prior art at the time of filing, are neitherexpressly nor impliedly admitted as prior art against the presentdisclosure.

SUMMARY

A valve assembly for a fuel tank system including a fuel tank having afuel tank outlet and a purge canister includes a main valve and a safetycheck valve. The main valve can be configured to move from a closedposition to an open position. The main valve can have a main valve firstport fluidly coupled to the outlet of the fuel tank and a main valvesecond port fluidly connected to the purge canister. The safety checkvalve can be configured to move from an open position to a closedposition upon a pressure drop at the fuel tank outlet exceeding apredetermined threshold. The safety check valve can have a safety checkvalve first port fluidly coupled to the outlet of the fuel tank and asafety check valve second port fluidly coupled to the purge canister.

According to additional features, the main valve second port and thesafety valve second port collectively comprise a valve assembly outletthat is fluidly connected to the purge canister. The safety check valvecan further include a check valve body, a check ball assembly and acheck valve biasing member. The check valve body can include the checkvalve first port, the check valve second port and a check valve seat.The check valve biasing member can normally urge the check ball assemblyaway from the check valve seat. When a predetermined threshold pressureis experienced into the safety valve first port, the check ball assemblyis urged toward the check valve seat against the bias of the check valvebiasing member. The check ball assembly can comprise a first check balland a second check ball. The first and second check balls can be formedof one of (i) plastic and (ii) synthetic rubber and fluoropolymer.

According to other features, the main valve can be configured to movefrom a closed position to an open position during a two-stage operation.The main valve further comprises a solenoid, an armature and a poppet.The armature can be associated with the solenoid and be configured toenergize and translate the armature in a direction along itslongitudinal axis. The poppet can have an opening. The poppet can beretained at a distal end portion of the armature. The poppet can beretained at the distal end portion of the armature by a retaining ring.An annular space can be defined between the distal end portion of thearmature and the opening. The pressure can escape through the openingduring a first stage of the two-stage operation. A first o-ring can bepositioned between the poppet and the valve body on a valve seat at themain valve second port. The poppet can be configured to be held downagainst the first o-ring and the valve seat from pressure in the fueltank. The main valve and the safety valve can be distinct components.

According to other features, a second o-ring can be disposed around thedistal end of the armature and configured to selectively move againstthe poppet and close the annular space when the solenoid isde-energized. The second o-ring can be configured to move away from thepoppet when the solenoid is energized during the first stage of thetwo-stage operation. The armature can pull the poppet off of the seatduring a second stage of the two-stage operation when a threshold amountof pressure drop has occurred through the annular space during the firststage.

A valve assembly for a fuel tank system including a fuel tank having afuel tank outlet and a purge canister, the valve assembly fluidlycoupled between the fuel tank and the purge canister includes a mainvalve and a safety check valve. The main valve can be configured to movefrom a closed position to an open position during a two-stage operation.The main valve can have a main valve first port fluidly coupled to anoutlet of the fuel tank and a main valve second port fluidly connectedto the purge canister. The safety check valve can be configured to movefrom an open position to a closed position upon a pressure drop at thefuel tank outlet exceeding a predetermined threshold. The safety checkvalve can have a safety check valve first port, a safety check valvesecond port, a check ball assembly and a check valve biasing member. Thesafety check valve first port can be fluidly coupled to the outlet ofthe fuel tank. The safety check valve second port can be fluidly coupledto the purge canister. The check valve biasing member can normally urgethe check ball assembly away from the check valve seat.

According to other features, when a predetermined threshold pressure isexperienced into the safety valve first port, the check ball assemblycan be urged toward the check valve seat against the bias of the checkvalve biasing member. The check ball assembly can include a first checkball and a second check ball. The first and second check balls can beformed of one of (i) plastic and (ii) synthetic rubber andfluoropolymer. The main valve and the safety valve can be distinctcomponents.

The main valve further comprises a solenoid, an armature and a poppet.The armature can be associated with the solenoid and be configured toenergize and translate the armature in a direction along itslongitudinal axis. The poppet can have an opening. The poppet can beretained at a distal end portion of the armature. The poppet can beretained at the distal end portion of the armature by a retaining ring.An annular space can be defined between the distal end portion of thearmature and the opening. The pressure can escape through the openingduring a first stage of the two-stage operation. A first o-ring can bepositioned between the poppet and the valve body on a valve seat at themain valve second port. The poppet can be configured to be held downagainst the first o-ring and the valve seat from pressure in the fueltank.

According to other features, a second o-ring can be disposed around thedistal end of the armature and configured to selectively move againstthe poppet and close the annular space when the solenoid isde-energized. The second o-ring can be configured to move away from thepoppet when the solenoid is energized during the first stage of thetwo-stage operation. The armature can pull the poppet off of the seatduring a second stage of the two-stage operation when a threshold amountof pressure drop has occurred through the annular space during the firststage.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will become more fully understood from thedetailed description and the accompanying drawings, wherein:

FIG. 1 is a schematic illustration of a fuel tank system having anevaporative emissions control system including a valve assemblyincluding a main valve and a safety check valve constructed inaccordance to one example of the present disclosure;

FIG. 2 is a close-up view of the main valve of FIG. 1 according to oneexample of the present disclosure and identifying a first stage openingand a second stage opening;

FIG. 3 is a sectional view of the safety check valve of FIG. 1 and shownin a normally open position according to one example of the presentdisclosure;

FIG. 4 is a sectional view of the safety check valve of FIG. 1 and shownin a closed position; and

FIG. 5 is a plot of flow rate and pressure experienced at the safetycheck valve according to one configuration of the present disclosure.

DETAILED DESCRIPTION

With initial reference to FIGS. 1-5, a fuel tank system constructed inaccordance to one example of the present disclosure is shown andgenerally identified at reference number 10. The fuel tank system 10 cangenerally include a fuel tank 12 configured as a reservoir for holdingfuel to be supplied to an internal combustion engine via a fuel deliverysystem, which includes a fuel pump (not specifically shown). Acontroller 14 can be configured to regulate the operation of the engineand its fuel delivery system. The fuel tank 12 is operatively connectedto an evaporative emissions control system 20 that includes a purgecanister 22 adapted to collect fuel vapor emitted by the fuel tank 12and to subsequently release the fuel vapor to the engine. The controller14 can also be configured to regulate the operation of evaporativeemissions control system 20 in order to recapture and recycle theemitted fuel vapor. The fuel tank system 10 can be incorporated ontraditional fuel tanks and on fuel tanks configured for use on hybridelectric vehicles.

The evaporative emissions control system 20 includes a valve assembly30. The controller 14 can be adapted to regulate the operation of avalve assembly 30 to selectively open and close the valve, in order toprovide over-pressure and vacuum relief for the fuel tank 12. The valveassembly 30 can be configured to control a flow of fuel vapor betweenthe fuel tank 12 and the purge canister 22. The valve assembly 30includes a main valve 40 and a safety check valve 42. While the mainvalve 40 and the safety check valve 42 are shown as distinct componentsin FIG. 1, they may be provided in a single valve assembly. The mainvalve 40 is operated during refueling. The safety check valve 42 isincorporated to handle venting flow. The safety check valve 42 isnormally open and configured to check or close when a flow or pressuredrop exceeds a threshold.

The main valve 40 generally include a valve body 50 having a first port52 that is fluidly connected to a fuel tank outlet 53 of the fuel tank12 and a second port 54 that is fluidly connected to a valve assemblyoutlet 55 of the valve assembly 30. The valve assembly outlet 55 can befluidly connected to the canister 22 and in some examples a filler neckof the fuel tank 12. The main valve 40 further includes a solenoid 56that can energize to translate an armature 60 in a direction generallyalong its longitudinal axis. A poppet 64 is retained at a distal endportion 66 of the armature 60 by a retaining ring 68. Specifically, thedistal end 66 of the armature 60 extends through an opening 70 definedthrough the poppet 64. Lash exists between the distal end 66 of thearmature 60 and the poppet 64. An annular space 72 is defined betweenthe distal end portion 66 of the armature 60 and the opening 70 of thepoppet 64. An o-ring 74 is positioned between the poppet 64 and thevalve body 50 on a valve seat 76 at the second port 52. The poppet 64 isheld down on the valve seat 76 from pressure in the fuel tank 12.

As will be described herein, the main valve 40 is configured to open intwo stages. When the main valve 40 is de-energized, the armature 60 ispushed down (toward the second port 54). An armature o-ring 77 is incontact with the poppet 64 closing the annular space 72. As the annularspace 72 is sealed and the seat 76 is sealed, no leakage exists throughsecond port 54. When a refueling event exists, the main valve 40 isenergized. The poppet 64 is still held down against the o-ring 74 at theseat 76 because of the pressure experienced in the fuel tank 12. Whenthe main valve 40 is energized, the armature 60 is pulled upward (awayfrom the second opening 54) causing the armature o-ring 77 to move awayfrom the poppet 64 permitting vapor to slowly escape (or bleed) throughthe annular space 72. In one example, grooves are defined on the distalend portion 66 of the armature 60 to further facilitate the bleeding ofpressure. Pressure is slowly dropped upstream of the main valve 40. Whenthe pressure (upstream of the main valve 40) decreases to apredetermined level, the armature 60 is permitted to pull further upwardlifting the poppet 64 off the seat 76 (second stage). Again, theretaining ring 68 allows the armature 60 to lift the poppet 64 off ofthe seat 76.

As a result, the main valve 40 offers a two-stage opening feature. Afirst stage occurs when flow is permitted through a first stage openingS1 at the annular space 72. A second stage occurs when flow is permittedthrough a second stage opening S2 when the poppet 64 is lifted off ofthe seat 74. A rapid depressurization is allowed between the fuel tank12 and the downstream canister 22. By way of example only, the annularspace 72 is capable of depressurizing about 100 Liters at 35 kPa inabout 1 minute. The poppet 64 will lift off of the seat 74 at about 13kPa. The fuel tank 12 completes depressurization rapidly afterward.

The safety check valve 42 has a check valve body 78. The safety checkvalve 42 has a first port 80 and a second port 82. The fuel tank outlet53 can collectively comprise the first port 52 of the main valve 40 andthe first port 80 of the safety check valve 42. The valve assemblyoutlet 55 can collectively comprise the second port 54 of the main valve40 and the second port 82 of the safety check valve 42.

In the example shown, the first port 80 is provided through an upstreamplug 84 and the second port 82 is provided through a downstream plug 86.The check valve body 78 has a check valve seat 94. A check valve biasingmember 96 urges a check ball assembly 98 including a first and a secondcheck ball 100, 102 away from the seat 94 in a normally open position(FIG. 3). In the normally open position vapor flow is permitted betweenthe check ball 100 and the valve seat 94. When a predetermined thresholdpressure is experienced into the first port 80, the check ball assembly98 is urged toward the seat 94 against the bias of the biasing member 96and the first check ball 100 sealingly engages the seat 94 (FIG. 4). Thesafety check valve 42 provides a mechanically actuated valve. The safetycheck valve 42 will close when the difference of the pressure in thefuel tank 12 and the pressure of venting system outside of the fuel tank12 (to the canister 22) of the evaporative emissions control system 20is higher than a closing pressure of the safety check valve 42. Theventing path from the fuel tank 12 to the venting system outside of thefuel tank 12 is closed. In one example, the check balls 100 and 102 maybe formed of plastic. In another example, the check balls 100 and 102may be formed of synthetic rubber and fluoropolymer elastomer such asViton manufactured by DuPont.

The safety check valve 42 provides a safety function by inhibiting highpressures from passing from the first port 82 to the second port 84.Explained further, if there is a large pressure experienced in the fueltank 12, the safety check valve 42 moves to the closed position (checkball 100 ultimately moves against the seat 94, see FIG. 4) to inhibitflow out of the second port 82. The safety check valve 42 will seal offany vapor from escaping through the second port 82. In oneconfiguration, the check ball assembly 98 can be urged closed around 3liters per minute (see also FIG. 4).

The safety check valve 42 can further allow adjustment of preload of thespring 96. A threaded connection 110 is provided between the check valvebody 78 and the downstream plug 86. The downstream plug 86 can beadjusted relative to the check valve body 78 to alter the preload of thespring 96. In this regard, the safety check valve 42 can be adjusted toaccommodate different opening pressures for different vehicleapplications. It is appreciated however that the threaded connection 110may alternatively be a fixed connection.

With particular reference to FIG. 4, the safety check valve 42 can beconfigured to close at around 2.5 kPa at flow rates between 2 and 5liters per minute (LPM). As can be appreciated, the pressure can beadjusted such as by modifying the spring rate of the check valve biasingmember 86.

The foregoing description of the examples has been provided for purposesof illustration and description. It is not intended to be exhaustive orto limit the disclosure. Individual elements or features of a particularexample are generally not limited to that particular example, but, whereapplicable, are interchangeable and can be used in a selected example,even if not specifically shown or described. The same may also be variedin many ways. Such variations are not to be regarded as a departure fromthe disclosure, and all such modifications are intended to be includedwithin the scope of the disclosure.

What is claimed is:
 1. A valve assembly for a fuel tank system includinga fuel tank having a fuel tank outlet and a purge canister, the valveassembly fluidly coupled between the fuel tank and the purge canister,the valve assembly comprising: a main valve configured to move from aclosed position to an open position, the main valve having a main valvefirst port fluidly coupled to the outlet of the fuel tank and a mainvalve second port fluidly connected to the purge canister; and a safetycheck valve that is configured to move from an open position to a closedposition upon a pressure drop at the fuel tank outlet exceeding apredetermined threshold, the safety check valve having a safety checkvalve first port fluidly coupled to the outlet of the fuel tank and asafety check valve second port fluidly coupled to the purge canister,the safety check valve comprising: a check valve body including thecheck valve first port, the check valve second port and a check valveseat; a check ball assembly including a first check ball and a secondcheck ball; and a check valve biasing member that normally urges thecheck ball assembly away from the check valve seat, when a predeterminedthreshold pressure is experienced into the safety valve first port, thecheck ball assembly is urged toward the check valve seat against thebias of the check valve biasing member.
 2. The valve assembly of claim 1wherein the main valve second port and the safety valve second portcollectively comprise a valve assembly outlet that is fluidly connectedto the purge canister.
 3. The valve assembly of claim 1 wherein the mainvalve and the safety check valve are distinct components.
 4. The valveassembly of claim 1 wherein the first and second check balls are formedof one of (i) plastic and (ii) synthetic rubber and fluoropolymer. 5.The valve assembly of claim 1 wherein the main valve is configured tomove from a closed position to an open position during a two-stageoperation, wherein the main valve further comprises: a solenoid; anarmature associated with the solenoid, wherein the solenoid isconfigured to energize and translate the armature in a direction alongits longitudinal axis; and a poppet having an opening, the poppetretained at a distal end portion of the armature.
 6. The valve assemblyof claim 5 wherein the poppet is retained at the distal end portion ofthe armature by a retaining ring.
 7. The valve assembly of claim 6wherein an annular space is defined between the distal end portion ofthe armature and the opening, wherein pressure escapes through theopening during a first stage of the two-stage operation.
 8. The valveassembly of claim 7, further comprising a first o-ring positionedbetween the poppet and the valve body on a valve seat at the main valvesecond port, and wherein the poppet is configured to be held downagainst the first o-ring and the valve seat from pressure in the fueltank.
 9. The valve assembly of claim 8, further comprising a secondo-ring disposed around the distal end of the armature and configured toselectively move against the poppet and close the annular space when thesolenoid is de-energized, and wherein the second o-ring is configured tomove away from the poppet when the solenoid is energized during thefirst stage of the two-stage operation.
 10. The valve assembly of claim9 wherein the armature pulls the poppet off of the seat during a secondstage of the two-stage operation when a threshold amount of pressuredrop has occurred through the annular space during the first stage. 11.A valve assembly for a fuel tank system including a fuel tank having afuel tank outlet and a purge canister, the valve assembly fluidlycoupled between the fuel tank and the purge canister, the valve assemblycomprising: a main valve configured to move from a closed position to anopen position during a two-stage operation, the main valve having a mainvalve first port fluidly coupled to an outlet of the fuel tank and amain valve second port fluidly connected to the purge canister; and asafety check valve that is configured to move from an open position to aclosed position upon a pressure drop at the fuel tank outlet exceeding apredetermined threshold, the safety check valve having: a safety checkvalve first port fluidly coupled to the outlet of the fuel tank; asafety check valve second port fluidly coupled to the purge canister; acheck ball assembly; and a check valve biasing member that normallyurges the check ball assembly away from a check valve seat.
 12. Thevalve assembly of claim 11 wherein when a predetermined thresholdpressure is experienced into the safety valve first port, the check ballassembly is urged toward the check valve seat against the bias of thecheck valve biasing member.
 13. The valve assembly of claim 12 whereinthe check ball assembly comprises a first check ball and a second checkball.
 14. The valve assembly of claim 13 wherein the first and secondcheck balls are formed of one of (i) plastic and (ii) synthetic rubberand fluoropolymer.
 15. The valve assembly of claim 11 wherein the mainvalve further comprises: a solenoid; an armature associated with thesolenoid, wherein the solenoid is configured to energize and translatethe armature in a direction along its longitudinal axis; and a poppethaving an opening, the poppet retained at a distal end portion of thearmature.
 16. The valve assembly of claim 15 wherein the poppet isretained at the distal end portion of the armature by a retaining ringand wherein an annular space is defined between the distal end portionof the armature and the opening, wherein pressure escapes through theopening during a first stage of the two-stage operation.
 17. The valveassembly of claim 16, further comprising: a first o-ring positionedbetween the poppet and the valve body on a valve seat at the secondport, wherein the poppet is configured to be held down against the firsto-ring and the valve seat from pressure in the fuel tank; and a secondo-ring disposed around the distal end of the armature and configured toselectively move against the poppet and close the annular space when thesolenoid is de-energized, wherein the second o-ring is configured tomove away from the poppet when the solenoid is energized during thefirst stage of the two-stage operation.
 18. The valve assembly of claim11 wherein the main valve and the safety valve are distinct components.19. A valve assembly for a fuel tank system including a fuel tank havinga fuel tank outlet and a purge canister, the valve assembly fluidlycoupled between the fuel tank and the purge canister, the valve assemblycomprising: a main valve configured to move from a closed position to anopen position, the main valve having a main valve first port fluidlycoupled to the outlet of the fuel tank and a main valve second portfluidly connected to the purge canister, wherein the main valve isconfigured to move from a closed position to an open position during atwo-stage operation, wherein the main valve further comprises: asolenoid; an armature associated with the solenoid, wherein the solenoidis configured to energize and translate the armature in a directionalong its longitudinal axis; and a poppet having an opening, the poppetretained at a distal end portion of the armature; and a safety checkvalve that is configured to move from an open position to a closedposition upon a pressure drop at the fuel tank outlet exceeding apredetermined threshold, the safety check valve having a safety checkvalve first port fluidly coupled to the outlet of the fuel tank and asafety check valve second port fluidly coupled to the purge canister;wherein the main valve second port and the safety valve second portcollectively comprise a valve assembly outlet that is fluidly connectedto the purge canister.
 20. The valve assembly of claim 19 wherein themain valve and the safety valve are distinct components.